POS0498 RISK WEIGHT CALCULATION OF CANDIDATE VARIANTS FOR INCIDENT MAJOR OSTEOPOROTIC FRACTURE IN PATIENTS WITH RHEUMATIC DISEASES
Authors: I. Yoshii, N. Sawada
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Incidental osteoporotic fractures are one of the serious comorbidities in patients with rheumatic disease (RD). However, no comprehensive treatment criteria exist to prevent these fractures. <h3>Objectives</h3> The purpose of this study is to develop criteria and assess the validity of the criteria using retrospective cohort data. <h3>Methods</h3> Patients with RDs who were treated for more than one year were picked up in the study. The patients were followed up with blood tests including cystatin C (CysC) every 3 months. Bone mineral density (BMD) using dual-energy X-ray absorptive densitometry was measured annually. Comorbidities, presence of prevalent osteoporotic fracture, and habitual tastes such as alcohol drinking and current smoking were picked up at the initiation of treatment (baseline). The primary endpoint was incidental osteoporotic fractures (inc-OF). Patients were followed up until December 2022, unless censored by death, loss of follow-up, or dropping out due to admission to a nursing home. Candidate risk factors, with these significant differences between groups with OF and without OF, were demonstrated using Mann-Whitney U-test, for incident OF and were evaluated using a cox regression analysis with the univariate model. Risk weights of each factor were calculated using risk ratio and beta-value. The total risk weight for each patient (TRW) was determined by summarizing the risk weight of each factor. Receiver operating characteristics (ROC) analysis was tested in order to determine the area under the curve (AUC) and the cut-off index (COI). Finally, a chi-square test was also performed in regard to anti-osteoporotic drug administration after baseline (OPD). <h3>Results</h3> A total of 1228 patients in these 345 males and 883 females were included. The mean age at baseline was 77.7 years old, and the mean follow-up period was 40.2 months. Background RDs were 761 with rheumatoid arthritis, 163 with psoriatic arthritis, 99 with Sjogren syndrome, 65 with pustulosis palmaris et plantaris, 48 with systemic lupus erythematosus, 24 with ankylosing spondylitis, 19 with systemic sclerosis, 16 with ulcerative colitis, 12 with Behçet's disease, 4 with polymyositis/dermatomyositis, 3 with mixed connective tissue disease, 3 with familial Mediterranean fever, and 1 with polyarteritis nodosa. Picked-up factors were the presence of pre-OF, estimated glomerular filtration rate using CysC (eGFR), T-score in the lumbar spine (LS) and in the femoral neck (FN), number of comorbidities (nCom), presence of diabetes mellitus (DM), hypertension (HT), hyperlipidemia (HL), chronic obstructive pulmonary diseases (COPD), insomnia, cognitive impairment (CI), musculoskeletal ambulation disability symptom complex (MADS), disuse, neuromuscular diseases (NMD), and polypharmacy (PPs) at baseline. Risk ratios, beta-values, p-values, and calculated risk weights in these factors were shown in Table 1. The mean TRW in patients was 66.7 in the group with inc-OF and 138.4 in the group with no incident OF (p&lt;0.001). The AUC was 0.787 and the COI was 93.6 with 80.4% and 68.8% of sensitivity and specificity, respectively (p&lt;0.001). OPD was administrated in 341 patients of the 471 TRW positive group in whom 299 did not have inc-OF, whereas, in the 164 patients of the 757 TRW negative group, only 10 had inc-OF. <h3>Conclusion</h3> A novel evaluation system for osteoporosis treatment should be a numerical system that summarizes adding risk weight of each candidate factor. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.